It is known to position a splitter device behind the circular saw blade of a table saw to maintain separation of the cut material by virtue of its location in the kerf. The term behind is used herein to mean downstream of the saw blade in the direction of movement of a work piece past the blade. Splitters generally consist of a thin piece of metal supported in the plane of the saw blade. A splitter functions to prevent the cut portion of the material from rubbing against the upwardly moving rear portion of the saw blade, which could result in dangerous kickback of the work piece and/or charring of the work piece surface. Various types and arrangements of splitters are well known in the art. See for example, U.S. Pat. No. 482,507 which issued on Sep. 13, 1892 and describes a kerf spreader that is affixed to a saw table. It is also known to utilize a European-style riving knife, which is a splitter that moves with the saw blade rather than being affixed to the saw table.
Modern table saws are often provided with a combination splitter, anti-kickback pawl and guard. Certain table saw operations require the removal of such combination devices due to physical interferences, such as the guard interfering with narrow ripping, the guard and the anti-kickback pawls obstructing tenon cutting when the board is vertically oriented, and the anti-kickback pawls causing binding on certain type of cross cutting. The removal and reinstallation of such devices is often troublesome and time consuming, such as with combination devices shown in U.S. Pat. Nos. 4,625,604 and 6,405,624. Many table saw owners permanently remove their splitter combination devices to avoid such inconvenience.
FIG. 1 is a top view illustration of a prior art splitter being used on a table saw. A saw blade 10 extends through a saw slot in a work surface 12 upon which a work piece 14 is supported. As the work piece 14 is urged past the saw blade 10, a saw cut or kerf 16 is created that separates the off-cut piece 18 from the keeper piece 20. Straight line movement of the work piece 14 past the saw blade 10 is ensured by keeping an alignment edge 22 of the work piece 14 against a rip fence 24, which is, in turn, securely supported to extend above the work surface 12 in a plane parallel to the saw blade 10. Splitter 26 is supported in a position behind the saw blade 10 and extends above the work surface 12 within the kerf 16.
Proper alignment of the splitter 26 relative to the saw blade 10 is known to be important for proper functioning of the splitter 26. A splitter on a circular table saw is generally thinner than the saw blade and the kerf it creates. If the splitter 26 is directly centered behind the saw blade 10, a small gap will exist between the splitter 26 and the off-cut piece 18 as well as between the splitter 26 and the keeper piece 20. Such gaps reduce the effectiveness of the splitter by allowing the respective portions of the work piece to move toward the saw blade 10. Often, such a splitter 26 is aligned and installed to be flush with the side of the saw blade 10 facing the rip fence 24 to deny the keeper piece 20 from contacting the saw blade 10. However, precise alignment of a splitter relative to a saw blade is known to be a difficult task. One known method of alignment is to place a straight edge against the side of the saw blade, then to affix the splitter into position against the straight edge. This method achieves alignment of one side of the splitter with one side of the saw blade; however, it augments the gap remaining between the other side of the splitter and the other side of the saw blade.
Splitters that maintain contact with both the off-cut piece 18 and the keeper piece 20 are also known. U.S. Pat. No. 6,715,388 issued on Apr. 6, 2004, describes a rotatable splitter holder mounted behind a saw blade. The position of a splitter pin extending into the kerf above the holder is controlled by the rotation of the holder. Two pins may be positioned on the holder, one on each opposed side of the axis of rotation, to make contact with both the off-cut piece and the keeper piece. The rotation of such a two-pin holder will change the width between the pins within the kerf, thereby accommodating various widths of saw blades. U.S. Pat. No. 3,566,934 issued on Mar. 2, 1971, describes a splitter that includes a plurality of resilient contacts that project toward the opposed sides of the kerf to make contact with both the off-cut piece and the keeper piece. If such dual-contact splitters are not precisely centered behind the saw blade, excessive contact pressure may be exerted against one side of the kerf, while inadequate or no pressure may be exerted against the opposed side.